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IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com

IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com

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  • P. Nagarjuna, k. Devaki Devi / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue5, September- October 2012, pp.535-539 Design And Optimization Of Sheet Metal Control Arm For Independent Suspension System *P. Nagarjuna, **k. Devaki Devi, * (Department of Mechanical Engineering, G Pulla Reddy Engineering College, Kurnool, A.P., India,) ** (Department of Mechanical Engineering, G Pulla Reddy Engineering College, Kurnool, A.P., India,)ABSTRACT: medium carbon steels, which are sufficiently Suspension system of an automobile strong as shown in figure.1.plays an important role in ensuring the stability  This forged component is bulky and heavierof the automobile. Although it has been achieved accounting for an increase in vehicle weight.to a considerable extent, another major aspect of Moreover, the process of forging the controlsuspension system is passenger car is luxury. A arm is a costlier process as it involves use oflot of research is going on in this direction, which complex dies .it also needs a proper care inled to the development of independent suspension heating process so as not to effect the strengthsystem. of the component. Control arm plays a major role inindependent suspension system. It is generallymade of forged steel which has considerabledisadvantages such as weight, cost etc. Theproject involves the development of sheet metalcontrol arm, which has many advantages overforged metal. The component has been modeledusing the curves extracted from workspaceavailable in PRO-E. This model is translated intoSTEP file, which is than retrieved in‘Unigraphics’ for analysis. The model is subjected to different loadconditions and thus analyzed using StructuresP.E solver. The stress and stiffness of the model isstudied from the results obtained from analysis toverify the success of the designI. INTRODUCTION:I.1 CONTROL ARM: Figure.1: A Suspension System with Ball Joint and Control arm is the major part of the Controlindependent suspension system. It forms connection I.2 FORGING OPERATION:between the wheel hub and the automobile chassis . Forging is the operation where the metal isThe main functions of control arm are: heated and then a force is applied to manipulate the To form a rigid connection between the chassis metal in such way that the required final shape is and wheel hub, to which wheel is attached. obtained. This is the oldest of the metal working It allows the wheel, the required degrees of processes. freedom for proper steering and suspension abilities. I.2.1 Forging types: It supports the spring and dampers, which form  Smith forging: this is the traditional forging the major components for shock absorbing. operation done openly or in open dies by the village black smith or modern shop floor by To do these functions properly the control arm manual hammering or by power hammers. needs to sufficiently strong. Depending upon the position of the control arm, there are mainly two  Drop forging: This operation done in closed types of control arms impression dies by means of the drop hammer .Here the force shaping the component is applied in a series of blows. Upper and lower control arm. The springs are and shock absorbers are supported between  Press forging: Similar to drop forging, the press these arms, which prevents lateral movement of forging is also done in closed impression dies springs. Conventionally the control arms are with the exception that the forces is continuous manufactured by the process of forging the squeezing type applied by the hydraulic presses. Machine forging: Unlike the drop or press forging where the material drawn out, in machine 535 | P a g e
  • P. Nagarjuna, k. Devaki Devi / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue5, September- October 2012, pp.535-539forging, the material is upset to get the desired The design is mainly based on theshape. The control arms are mostly manufactured by consideration like decrease of weight and cost etc.drop forging process. The existing forged component is heavy and its manufacturing is complex. So in order to make moreAdvantages: reliable it is replaced by sheet metal component Uniformity of qualities for parts subjected which is light and involves more simple operations.to high stress and loads. The workspace for the design is extracted from the Close tolerances existing forged model. The design and modeling is Speed of production done using CAD software,”PRO-E”. To obtains the workspace the curves are extracted from the extremeDisadvantages: edges of the workspace model and copied to a new High tool cost file. Modeling is done using surfaces. Design with High tool maintenance surfaces is simpler and complex shapes can be No core holes modeled using operations like merging, trim etc. Limitations in size and shape After the creation of the model using surfaces the surface is thicken to 3.5mm using solid protrusion.I.2.2 Sheet Metal Operation: The rod and washer are designed as per The sheet metal operation basically required dimensions. A standard ball joint of suitableinvolves the process of press working consists of dimension is modeled. The thickness of the sheetshearing and then plastically working the metal to metal component is 3.5mm. Practically the ball jointthe desired finished shape and the size through a few and the rod are attached to the sheet metalquick strokes under heavy loads . component using wields. Sheet metal component can be manufactured by making two bends along withI.2.3 Press Tool Operations: form operation and one roll operation. The design is Shearing shearing, improvised based on the analysis results and a finalblanking, model is developed.piercing,trimming, shaving. Tension stretchforming Compression coining,sizing, ironing,hobbing Tension and compression drawing,spinning, bending,forming andembossingAdvantages: It is one the cheapest and fastest way ofcomplete manufacture of a component.Disadvantages: Sheet metal operations are generally performedon the sheets of thickness less than 5mm.II. DESIGN OF CONTROL ARMII.1 DESIGN CONSIDERATIONS: Figure.2: Existing Forged Model  Space  Strength  Weight  Manufacturing feasibility  CostII.2 DESIGN PROCEDURE: 536 | P a g e
  • P. Nagarjuna, k. Devaki Devi / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue5, September- October 2012, pp.535-539 stiffening, large deflections and large strain capabilities.Figure.3: Sheet Metal Control Arm Figure.6: Tetrahedral ElementII.3 MANUFACTURING PROCESS:1. A flat blank is created from the design.2. The blank is then subjected to vertical draw. Figure4: Vertical Draw1. Flange inside operation is performed; it is done in2 to 3 stage.2. The sheet is rolled on to the back rod using rollingpunches. It is also performed in 2 to 3 stages.3. Finally, holes are pierced in the component Figure7: Meshed Component Figure5: Flange InsideIII.ANALYSIS The final model is exported by “steptranslator” to a step file. The created step file isimported into Unigraphics’ software and convertedto Unigraphics part file. Environment :Structures P.E./Linear Statics Plus Analysis : StructuralLinearity : Linearity:Time dependency : Steady-stateSolver : Structures P.E. Figure 8: Rigid Links In HoleIII.1.MESHING: At the ball joint hole a central node is The model is meshed with tetrahedral 10 created and rigid links are created connectingelements. The element is defined by ten nodes between the central node and nodes created on thehaving three degrees of freedom at each node, hole during meshing of the component. This is totranslation in the nodal x, y, and z direction. The make nearest to practicality .The point loads areelement also has plasticity creep, swelling, stress applied at that central node. 537 | P a g e View slide
  • P. Nagarjuna, k. Devaki Devi / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue5, September- October 2012, pp.535-539Number of elements created = 28276Number of nodes created =53272The analysis is carried for three different loadconditions.III.2.LOADS AND BOUNDARY CONDITIONS:The Model has been analyzed for the following loadcases.III.2.1. Incidental Load case:These loads act on the vehicle when it is subjected tohigh and sudden decelerating forces.Loads:Load (N) 𝑓𝑋 𝑓𝑌10910 4350 All the loads were applied at the point D.Boundary Conditions:z translation fixed for point D.x, y, z translations fixed for point E1. Figure 9: Points Where Loads and Boundaryy, z translations fixed for point E2. Conditions To Be AppliedIII.2.2Maximum Load case:These load conditions are observed during regularoperations of the vehicle. IV.RESULTS AND DISCUSSIONSLoads: IV.1. INCIDENTAL LOAD CASE: Load (N) The maximum stress observed during this case is 513 MPa 𝑓𝑋 𝑓𝑌 The yield strength of the material is 540 MPa 7880 5860 It is observed that, the stress obtained is less than the yield strength of material .So theAll the loads were applied at the point D. control arm withstands the incidental loads.Boundary Conditions:z translation fixed for point D. IV.2. MAXIMUM LOAD CASE:x, y, z translation and rotations fixed for point E1. The maximum stress observed during this case isx, y, z translation and rotations fixed for point E2. 466 MPaThe yield strength of the material is 540III.2.3Stiffness calculations: MPaLoads: It is observed that, the stress obtained is less than the Load (N) yield strength of material .So the control arm withstands the maximum loads. 𝑓𝑋 𝑓𝑌 1000 1000 IV.3. STIFFNESS LOAD CASE:All the loads were applied at the point D. Stiffness calculations: Stiffness=force/maximum deflectionBoundary Conditions: 𝐾 𝑋 =1000/.1439=5263N/mmz translation fixed for point D. 𝐾 𝑌 =1000/.02643=37835N/mmx,y,z translations fixed for point E1. Direction Objective Stiffness Obtained Stiffnessy,z translations fixed for point E2. N/mm N/mm 𝐾𝑋 3000 5263III.3MATERIAL PROPERTIES:Modulus of Elasticity =210000 MPa 𝐾𝑌 24000 37835Poisson’s ratio = 0.3 From the stiffness calculations it is observed that,Steel (safe stress = 540 MPa) the control arm satisfies the stiffness requirements in It is finally solved using structures P.E solver .The X and Y-directions.results obtained are retrieved through post processorsection. 538 | P a g e View slide
  • P. Nagarjuna, k. Devaki Devi / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue5, September- October 2012, pp.535-539  Ease of manufacturing. The sheet metal operations are simple and cheap when compared to the forged operations.  Ball joints of different standards can be used by varying the size of the hole by changing the piercing tool.  The cost of component is reduced to a considerable extent as the raw material used for sheet metal component is very cheap than that used for forged component.  The results obtained from analysis infer that theFigure10: Incident Load Case sheet metal component satisfies all the design considerations. The stresses obtained for different load conditions are within the limits. Stiffness is observed to be satisfactory. Hence, sheet metal control arm is more beneficial than forged control arm. REFERENCES [1]. R.B.Gupta, “Automobile Engineering”, Satya Prakash publications, 6t edition, 2003 [2]. Herb Adams, “Chassis Engineering”, Berkley publishing group, Newyork, 1993. [3]. www.leafukcar.com [4]. Kirpal Singh, “Automobile Engineering”,Figure11: Maximum Load Condition Standarad publishers, vol 1, 1998. [5]. www.tetra.com [6]. www.ukcar.com [7]. K.K Jain, and R.B.Asthana, “AutomobileEngineering”.Danpathrai publications. [8]. Heinz Heisler, “Modern Automobile Engineering”, McGraw Hill publishers, 2001. [9]. J.Reimpell, H.Stoll, J.W.Betzler, “The Automotive Chassis”, SAE International, 2nd edition, 2001.Figure12: Displacement (-X) In Y Direction [10]. P.N. Rao, “Manufacturing Technology”TATA McGraw Hill publishing company, 7th edition, 1987, pp 261-284. [11]. Hajra Choudhury, “Work Shop Technology”, Media promoters and publishers, 10th edition, 2000, pp 608-620. [12]. www.PTC.com [13]. www.unigraphics.com [14]. www.eds.comFigure13: Displacement (Z) In X DirectionV.CONCLUSIONS From the design and analysis data, it is observed that The weight of the component is decreased by 25% i.e. the weight of the forged model is 4.32 kg and the weight of the sheet metal model is 3.23kg. 539 | P a g e